The struggle between two different ethical and philosophical world views reached a climax in America last week as the House of Bishops in the Catholic Church expressed their discomfort with Joe Biden offering pollical support for abortion while demanding the right to receive the Eucharist as a faithful Catholic when his political views are in direct conflict to the faith.

Some commentators, like the eminent Ruth Gledhill writing in Christian Today, take a progressive view on this:

"It is difficult to see the decision of the US bishops this week to move forward with drafting a document that would in effective seek to penalise President Joe Biden for his support for the right to choose on abortion, as anything other than a political intervention."

In fact I think this has the situation upside down. This is in fact a spiritual intervention in a political debate which has been dominated by political and secular values, brought about because the most elevated political figure in the United States wants both the power of his office and the privileges of his faith.

The problem arises because the ethics of the faith he wants the privileges of have been contradicted, confronted and attacked by the politics he represents. Given such a stark contradiction, many people - and not just Catholic bishops - believe he is going to have to relinquish either his political views or the pretence he is being a faithful Catholic.

I remember the moment when my mind first began to change about abortion and began to abandon a purely political take on it. It was during a live broadcast on the BBC Sussex and Surrey Faith and Ethics show, which I was presenting at the time.

Until then I had taken the view that abortion was a feminist issue where if women claimed they had a right to control what went on in their body, who was I to argue with them? I wasn't a woman.

And more difficult still, I fell for the argument that since I had no scientific evidence that could prove when 'life' began in a foetus, I had no business pontificating that one moment more than another was the cut off point for the viability of life.

I pushed the whole issue to the corner of my eye and the back of my mind.

But during this particular broadcast a woman phoned in to argue about abortion. When contributors on a phone-in went on for more than a few seconds, I would sometimes do a quick internet search on the subject they wanted to discuss - in case there were facts I had overlooked that I needed to pay attention to.

While she was talking I was skimming internet pages and suddenly came across one that gave the figure (to that date) of destroyed babies in the UK since the Abortion Act. It was six million.

Now for my generation, six million is a particularly resonant number. It's the number of Jews the Nazis killed in the Holocaust.

Before I could stop, I found myself murmuring out loud; "six million deaths....it's the same number as the Holocaust" (which it was). My BBC bosses went ballistic. I was on the carpet the following morning: "You may never, ever again, make a connection on air between the number of abortions and the number of Jews killed in the Holocaust."

But worse was to come. As I began to read more widely, and I looked at child sacrifice in different non-Christian cultures, the most disturbing element was the link between the sacrifice of children and the propitiation of dark gods.

I wondered what this phenomenon would look like if we took the teaching of Jesus in St John's Gospel more seriously about this present world being held in the grip of a dominating evil, and asked ourselves if there was a link between the disposing of our pre-born children and the energising of evil in our culture?

Freud wrote about the power of Thanatos, a kind of death-wish buried deep in the human psyche. Social psychologists observing the increasing rates of depression, suicide and self-harm amongst our offspring, talk in terms of a cultural or unconscious death wish emerging in our society. Others have looked at the way in which we have jettisoned the historic Christian values that acted as a foundation for the better elements of our civilisation and asked if in their unthinking rejection, we are committing cultural self-harm.

Alternative perspectives present themselves when we examine this wholesale culling of pre-born infants in a different analytical framework than the simplistic feminist one we are used to in the media. The issues here go much further than the rather stark and simplistic one of women taking unilateral power over their own bodies.

I found myself being haunted by an intuition that we were in fact committing child sacrifice on an industrial scale. Maybe the gods we were placating were only simplistic ones like 'our own convenience' or 'the maintenance of a lifestyle' where the children who had been conceived posed an interruption to the life of the mother, or an inconvenience, an embarrassment or a threat to resources. But the puerileness of the gods we sacrificed our children to did not change the horror of the perception.

As things stand now the numbers of pre-born killed worldwide have risen to 56 million a year since 2010.

You can make a case that many of these foetuses are not people. But with late-term abortions becoming legitimised, it's harder to justify a point in the development of a child in the womb when you say, 'before this point it was not a human being.' The problem with that is that you end up being forced to take the view that has now become a political reality, that killing the fully formed child as it leaves the womb is legally justifiable (if morally wholly repugnant). The only other possible view is that it is a human being from conception.

If ever the point comes when you take the view that the moment when the embryo becomes a viable human being is conception, then any destruction after that point by an outside agency is a grave moral matter.

And this brings us to the matter of Biden and the Catholic bishops. As with all ethical arguments so much depends on your presuppositions. Pragmatists, feminists and relativists all presuppose that no great harm is done in the removing of a foetus.

Catholics (and some others) see the greatest harm being done in the destruction of any pre-born child.

The Catholic catechism teaches "Since the first century the Church has affirmed the moral evil of every procured abortion. This teaching has not changed and remains unchangeable."

Let us set aside for a moment the views of the feminists, relativists and pragmatists, and approach this matter from a Catholic point of view.

The moral teaching of the Church makes both the practice of abortion and the support for the practice of abortion, a most serious sin.

St Paul, in the earliest days of eucharistic teaching was passionately clear about the relationship between the eucharist and the soul. He takes an uncompromising approach that Eastern Orthodoxy and Catholicism have kept particular faith with.

"Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty concerning the body and blood of the Lord. Let a person examine himself, then, and so eat of the bread and drink of the cup. For anyone who eats and drinks without discerning the body eats and drinks judgment on himself. That is why many of you are weak and ill, and some have died." (1 Cor 11.27 ff)

The Catholic Church, not unreasonably, applies St Paul's warning of the most serious consequences flowing from impaired spiritual discernment to the wider moral life of the Christian.

Canon 916 of the 1983 Code of Canon Law is explicit:

"A person who is conscious of grave sin is not to celebrate Mass or receive the body of the Lord without previous sacramental confession unless there is a grave reason and there is no opportunity to confess; in this case the person is to remember the obligation to make an act of perfect contrition which includes which includes the resolution of confessing as soon as possible."

It could hardly be more clear. The act of abortion is a serious moral failure. Supporting or promoting abortion is a serious moral failure. You cannot come to the Eucharist without repenting of serious moral failure.

Jesus himself makes it clear that unfinished moral business has to be sorted out before presenting oneself in the context of a sacrifice:

"So if you are offering your gift at the altar and there remember that your brother has something against you, leave your gift there before the altar and go. First be reconciled to your brother, and then come and offer your gift." (Matt 5.23)

Let's borrow a leaf from the progressive's book for a moment. The puritanical world of thought crime insists that there are many thought crimes and moral defects that the perpetrators are not aware of. And so they talk to us of racism and unconscious bias. They point out that once you have been liberated from unconscious bias, you cannot fail to see the seriousness of the moral failure.

Catholics can say the same. We may disagree about the secular understanding of thought crime, but we can certainly say that once you have seen the horror of abortion, the scale of it, the effect of it both on mothers who have been affected by it and on society that has endorsed it and lives with the consequences of it, the moral issues present themselves in stark relief. Catholic insight and moral teaching could not be more clear.

In secular terms, one of the reasons why anti-abortion activists present the images of the bodies of small infants in the womb whose limbs have been cut off and severed in the act of aborting them, is to awaken the consciences of those who have closed their imaginations to the brutality of the act. It is to confront their unconscious bias, to save them from the bias, conscious or unconscious, from facing the implications of the suffering and brutality taking place in the womb.

But all this is taking place in the context of an enormously energised moral and ethical struggle which is dividing our culture.

At the heart of it is one of the deepest moral insights in the Judaeo-Christian way of looking at ourselves and the world. It is the assertion that human beings are made in the image of God, and have a sanctity, a moral probity that is a God-given right. And the implications of this stretch from the obvious, like an abhorrence of slavery, to how we treat those imprisoned in the justice system, through to the way we deal with each other sexually and politically.

It has the profoundest implications for euthanasia where Christians are fighting to save human beings from being 'disposed of' as wasted and wasteful commodities. It has the profoundest effect on defending the rights of the pre-born and mistaking a human being with a soul for a body part that can be amputated.

Many of us have become Catholics not least because in these times of moral turmoil, only the Catholic Church is refusing to give way to relativism, hedonism, the pleasure principle and brutalising dogmas about equality of outcome.

We are facing a powerful and dehumanising challenge from the Left of the political spectrum, which has always seen human beings as having value and significance only in so far as they conform to the ethical and ideological preferences of the State.,

No one is forcing President Biden to remain a Roman Catholic. But if the Unites States House of Bishops is reminding the President of the United States that his political office does not confer on him the right to pick and choose between the ethical values he finds politically convenient and those he does not, it is keeping faith with its deepest Christian and Catholic values. It is speaking truth to power. It is keeping the faith.

By all means welcome the President of the United States to the sacrament of the Eucharist, the 'medicine of immortality' as the early Church called it - but only after he has repented depriving the pre-born and our most vulnerable of their right to mortality.

Dr Gavin Ashenden is a former chaplain to the Queen. He blogs at Ashenden.org